This proposal requests funds for the purchase of a 500 MHz NMR spectrometer and associated data processing system to form the core of an interdisciplinary NMR center within the Institute of Biosciences and Bioengineering at Rice University. The spectrometer facility will support the research activities of six primary users and several secondary users from three academic departments. Major research projects with NIH support (four current, two pending) and secondary projects (four with current PHS support) span a range of biomedical problems. Several projects focus on the structure and function of proteins, including their interactions with ligands and/or cognate nucleic acids. These components will involve substantial application of two-dimensional methodologies. Other projects will use NMR to investigate eukaryotic cell metabolism in vivo, particularly in low-sensitivity systems. A third major application lies in the identification and structural analysis of complex natural and synthetic organic products which possess significant biological activities. The requested spectrometer is to be configured for maximum flexibility within the range of projected uses, including the purchase of a specialist probe for in vivo perfusion reactor experiments. The Ethernet-linked offline computer system will substantially enhance the efficiency of spectrometer use and provide a valuable resource for processing, analysis and display of complex spectroscopic data. In addition, molecular modeling based upon spectroscopic data will be performed on this computer. The University has made considerable efforts to demonstrate its commitment to the establishment of a high-field biomedical NMR facility on campus. Current financial commitments include the provision of new faculty and staff appointments, and renovation costs for an NMR instrument room. Rice is also willing to make necessary cost-sharing contributions to the purchase of this system.